Commonly Quotes (page 10)
For the fact is thatneither the grammarian nor any other person of skill ever makes a mistakein so far as he is what his name implies; they none of them err unlesstheir skill fails them, and then they cease to be skilled artists. Noartist or sage or ruler errs at the time when he is what his name implies; though he is commonly said to err.
Plato